An investigational drug administered by injection every eight weeks has been found to be effective and safe in preventing HIV infection among men who have sex with men and transgender women who have sex with men, in data released today demonstrating a form of long-acting biomedical HIV prevention to be as effective as daily medicine taken by mouth.

The long-acting effectiveness of the injected drug, cabotegravir was compared to the effectiveness of daily oral tenofovir in the HPTN 083 study across 43 sites in seven countries enrolling more than 4,500 participants who received placebos in addition to a random assignment of one of the two drugs.

Participants in the study represented some of the populations considered at highest risk for HIV infection, who also have faced traditionally, some of the greatest obstacles access to health service access. Two thirds of those enrolled were younger than 30, transgender women comprised 12% of participants and half of the United States participants identified themselves as black or African American (the other countries with trial sites are Argentina, Brazil, Peru, South Africa, Thailand and Vietnam). Investigators opened enrollment of the trial in 2016. Following an interim review concluding on May 14 that cabotegravir had been demonstrated to be highly effective in preventing HIV infection, investigators will end the use of placebos, notify participants of the results, and offer them access to the injected drug.

The HPTN 084 trial, which began in 2017, continues, comparing the effectiveness of the two drugs among 3,000 women across seven African countries.